"During repair and maintenance work, the pinnacle was found to be weak and showed clear signs of ageing. It was, therefore, brought down for repairs on Monday," an Archaeological Survey of India (ASI) official said.
The iron rod of the pinnacle was rusty and weak and needed to be replaced, he said, adding that fresh mortar has to be filled to provide stability to the surface "which remains exposed to elements".
Meanwhile, Conservation Assistant Ram Ratan today said that work has begun to restore the damaged pinnacle. Efforts would be made to re-install it within a week, another official said.
'Mud pack therapy' to remove dust particles and restore the lustre of the monument's marble surface is continuing, Ratan said.